diff --git a/prepare.py b/prepare.py
index 9ca12476a..aca19f628 100755
--- a/prepare.py
+++ b/prepare.py
@@ -418,7 +418,7 @@ def main(argv=None):
     argparser.add_argument(
         '--enable-non-free-codecs', help="Enable non-free codecs such as OpenH264, MPEG4, etc.. Final application must comply with their respective license (see README.md).", action='store_true')
     argparser.add_argument(
-        '-G' '--generator', help="CMake build system generator (default: Unix Makefiles, use cmake -h to get the complete list).", default='Unix Makefiles', dest='generator')
+        '-G', '--generator', help="CMake build system generator (default: Unix Makefiles, use cmake -h to get the complete list).", default='Unix Makefiles', dest='generator')
     argparser.add_argument(
         '-L', '--list-cmake-variables', help="List non-advanced CMake cache variables.", action='store_true', dest='list_cmake_variables')
     argparser.add_argument(